Britney Spears' ex opens up about singer's downward spiral

Britney Spears former boyfriend Adnan Ghalib has shed light on the singer's downward spiral, claiming that her staff kept her heavily medicated during their relationship which began in late 2007 and ended in early 2008.

Ghalib told a UK publication that on Christmas Day of 2007, just two months after the 'Womanizer' hit maker had lost custody of her two sons to former hubby Kevin Federline, she was despondent, News.com.au reported.

Ghalib said that the blonde beauty would have dozens of boxes of ADHD drug round the house and take them all the time.

He asserted that her staff gave her pills and within a few minutes her pupils were bulging and she would be wound up and frantic.

The mum-of-two would drink Red Bull all day, as many as 15 cans and all she wanted to eat was Cheetos and Cheez-It crisps, Ghalib said.

He added that Spears was going through 40 cigarettes a day and at certain times of day, she'd just stop and crash on the sofa for hours.